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Android 异步加载图片，使用LruCache和SD卡或手机缓存，效果非常的流畅

2014-08-07 16:17 836 查看
转载请注明出处http://blog.csdn.net/xiaanming/article/details/9825113

异步加载图片的例子，网上也比较多，大部分用了HashMap<String, SoftReference<Drawable>> imageCache ，但是现在已经不再推荐使用这种方式了，因为从 Android 2.3 (API Level 9)开始，垃圾回收器会更倾向于回收持有软引用或弱引用的对象，这让软引用和弱引用变得不再可靠。另外，Android 3.0 (API Level 11)中，图片的数据会存储在本地的内存当中，因而无法用一种可预见的方式将其释放，这就有潜在的风险造成应用程序的内存溢出并崩溃，所以我这里用得是LruCache来缓存图片，当存储Image的大小大于LruCache设定的值，系统自动释放内存，这个类是3.1版本中提供的，如果你是在更早的Android版本中开发，则需要导入android-support-v4的jar包（这里要注意咯）

为什么写这篇文章呢？

因为我之前做的项目中，也有异步加载图片，那时候用得是Thread去下载图片，每次下载图片都要new Thread去下载，而且还是并发去下载，每次都new 一个线程浪费内存，老板说服务器承受不起这么多的连接，叫我改成先获取一张图片之后再去获取下一张，这样子保存与服务器的连接为一个，服务器压力小了，然后楼主就想到线程池，线程池很好的帮我们管理并发的问题，并发的问题解决了，可是后面又出问题了，图片多了就出现OOM(OutOfMemory)异常，之后用了SoftReference，先用SoftReference中获取图片，SoftReference没有就开线程去下载，老板说你为什么不把图片在手机上做个缓存呢，于是我用了手机缓存，大概思路就是先从SoftReference中获取图片，如果SoftReference没有就去手机缓存中获取，手机缓存中没有就开启先从去下载，然后成功的解决了OOM的问题，前些天老板要我重构下代码，我也觉得之前写的代码耦合性太强，早就想改，然后之前看到guolin的Android照片墙应用实现，再多的图片也不怕崩溃的这篇文章，LruCache和滑动过程中取消下载任务，停下来的时候才去下载这2点比较好，值得我学习，然后我就将我的项目异步加载这一块改了下，发到这里做个记录吧，以后类似的异步加载图片直接拷贝代码，提交开发的效率

这篇文章做了哪些方面的优化

使用了线程池来管理下载任务
使用LruCache来缓存图片
使用手机来缓存图片
GridView滑动的时候取消下载任务，静止的时候进行下载，GridView滑动更加的流畅
降低了代码的耦合性，结构更加的清晰，便于以后重用

接下来我们先来看看项目的结构



FileUtils 文件操作的工具类，提供保存图片，获取图片，判断图片是否存在，删除图片的一些方法，这个类比较简单

[java]
view plaincopyprint?





package com.example.asyncimageloader; 

 
import java.io.File; 

import java.io.FileOutputStream; 

import java.io.IOException; 

 
import android.content.Context; 

import android.graphics.Bitmap; 

import android.graphics.Bitmap.CompressFormat; 

import android.graphics.BitmapFactory; 

import android.os.Environment; 

 
public class FileUtils { 

    /**
     * sd卡的根目录
     */ 
    private static String mSdRootPath = Environment.getExternalStorageDirectory().getPath(); 

    /**
     * 手机的缓存根目录
     */ 
    private static String mDataRootPath =
null; 
    /**
     * 保存Image的目录名
     */ 
    private final
static String FOLDER_NAME = "/AndroidImage"; 

     
     
    public FileUtils(Context context){ 

        mDataRootPath = context.getCacheDir().getPath(); 

    } 
     
 
    /**
     * 获取储存Image的目录
     * @return
     */ 
    private String getStorageDirectory(){ 

        return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED) ? 

                mSdRootPath + FOLDER_NAME : mDataRootPath + FOLDER_NAME; 

    } 
     
    /**
     * 保存Image的方法，有sd卡存储到sd卡，没有就存储到手机目录

     * @param fileName
     * @param bitmap  
     * @throws IOException
     */ 
    public void savaBitmap(String fileName, Bitmap bitmap)
throws IOException{ 
        if(bitmap ==
null){ 
            return; 
        } 
        String path = getStorageDirectory(); 
        File folderFile = new File(path); 

        if(!folderFile.exists()){ 

            folderFile.mkdir(); 
        } 
        File file = new File(path + File.separator + fileName); 

        file.createNewFile(); 
        FileOutputStream fos = new FileOutputStream(file); 

        bitmap.compress(CompressFormat.JPEG, 100, fos); 

        fos.flush(); 
        fos.close(); 
    } 
     
    /**
     * 从手机或者sd卡获取Bitmap
     * @param fileName

     * @return
     */ 
    public Bitmap getBitmap(String fileName){ 

        return BitmapFactory.decodeFile(getStorageDirectory() + File.separator + fileName); 

    } 
     
    /**
     * 判断文件是否存在
     * @param fileName
     * @return
     */ 
    public boolean isFileExists(String fileName){ 

        return new File(getStorageDirectory() + File.separator + fileName).exists(); 

    } 
     
    /**
     * 获取文件的大小
     * @param fileName

     * @return
     */ 
    public long getFileSize(String fileName) { 

        return new File(getStorageDirectory() + File.separator + fileName).length(); 

    } 
     
     
    /**
     * 删除SD卡或者手机的缓存图片和目录
     */ 
    public void deleteFile() { 

        File dirFile = new File(getStorageDirectory()); 

        if(! dirFile.exists()){ 

            return; 

        } 
        if (dirFile.isDirectory()) { 

            String[] children = dirFile.list(); 
            for (int i =
0; i < children.length; i++) { 
                new File(dirFile, children[i]).delete(); 

            } 
        } 
         
        dirFile.delete(); 
    } 
}<span style="font-family: Times New Roman; font-size: 14px;"> 

</span> 

package com.example.asyncimageloader;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.os.Environment;

public class FileUtils {
/**
* sd卡的根目录
*/
private static String mSdRootPath = Environment.getExternalStorageDirectory().getPath();
/**
* 手机的缓存根目录
*/
private static String mDataRootPath = null;
/**
* 保存Image的目录名
*/
private final static String FOLDER_NAME = "/AndroidImage";

public FileUtils(Context context){
mDataRootPath = context.getCacheDir().getPath();
}

/**
* 获取储存Image的目录
* @return
*/
private String getStorageDirectory(){
return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED) ?
mSdRootPath + FOLDER_NAME : mDataRootPath + FOLDER_NAME;
}

/**
* 保存Image的方法，有sd卡存储到sd卡，没有就存储到手机目录
* @param fileName
* @param bitmap
* @throws IOException
*/
public void savaBitmap(String fileName, Bitmap bitmap) throws IOException{
if(bitmap == null){
return;
}
String path = getStorageDirectory();
File folderFile = new File(path);
if(!folderFile.exists()){
folderFile.mkdir();
}
File file = new File(path + File.separator + fileName);
file.createNewFile();
FileOutputStream fos = new FileOutputStream(file);
bitmap.compress(CompressFormat.JPEG, 100, fos);
fos.flush();
fos.close();
}

/**
* 从手机或者sd卡获取Bitmap
* @param fileName
* @return
*/
public Bitmap getBitmap(String fileName){
return BitmapFactory.decodeFile(getStorageDirectory() + File.separator + fileName);
}

/**
* 判断文件是否存在
* @param fileName
* @return
*/
public boolean isFileExists(String fileName){
return new File(getStorageDirectory() + File.separator + fileName).exists();
}

/**
* 获取文件的大小
* @param fileName
* @return
*/
public long getFileSize(String fileName) {
return new File(getStorageDirectory() + File.separator + fileName).length();
}

/**
* 删除SD卡或者手机的缓存图片和目录
*/
public void deleteFile() {
File dirFile = new File(getStorageDirectory());
if(! dirFile.exists()){
return;
}
if (dirFile.isDirectory()) {
String[] children = dirFile.list();
for (int i = 0; i < children.length; i++) {
new File(dirFile, children[i]).delete();
}
}

dirFile.delete();
}
}<span style="font-family:Times New Roman;font-size:14px;">
</span>


Images类，提供图片资源的类，来自Android文档中BitmapFun中http://developer.android.com/training/displaying-bitmaps/index.html，里面一个静态的图片Url数组，这里面比较坑爹，因为是图片是google官网提供的，有时候会下载超时

[java]
view plaincopyprint?





package com.example.asyncimageloader; 

 
public class Images { 

 
    public final
static String[] imageThumbUrls =
new String[] { 
            "https://lh6.googleusercontent.com/-55osAWw3x0Q/URquUtcFr5I/AAAAAAAAAbs/rWlj1RUKrYI/s160-c/A%252520Photographer.jpg", 

            "https://lh4.googleusercontent.com/--dq8niRp7W4/URquVgmXvgI/AAAAAAAAAbs/-gnuLQfNnBA/s160-c/A%252520Song%252520of%252520Ice%252520and%252520Fire.jpg", 

            "https://lh5.googleusercontent.com/-7qZeDtRKFKc/URquWZT1gOI/AAAAAAAAAbs/hqWgteyNXsg/s160-c/Another%252520Rockaway%252520Sunset.jpg", 

            "https://lh3.googleusercontent.com/--L0Km39l5J8/URquXHGcdNI/AAAAAAAAAbs/3ZrSJNrSomQ/s160-c/Antelope%252520Butte.jpg", 

            "https://lh6.googleusercontent.com/-8HO-4vIFnlw/URquZnsFgtI/AAAAAAAAAbs/WT8jViTF7vw/s160-c/Antelope%252520Hallway.jpg", 

            "https://lh4.googleusercontent.com/-WIuWgVcU3Qw/URqubRVcj4I/AAAAAAAAAbs/YvbwgGjwdIQ/s160-c/Antelope%252520Walls.jpg", 

            "https://lh6.googleusercontent.com/-UBmLbPELvoQ/URqucCdv0kI/AAAAAAAAAbs/IdNhr2VQoQs/s160-c/Apre%2525CC%252580s%252520la%252520Pluie.jpg", 

            "https://lh3.googleusercontent.com/-s-AFpvgSeew/URquc6dF-JI/AAAAAAAAAbs/Mt3xNGRUd68/s160-c/Backlit%252520Cloud.jpg", 

            "https://lh5.googleusercontent.com/-bvmif9a9YOQ/URquea3heHI/AAAAAAAAAbs/rcr6wyeQtAo/s160-c/Bee%252520and%252520Flower.jpg", 

            "https://lh5.googleusercontent.com/-n7mdm7I7FGs/URqueT_BT-I/AAAAAAAAAbs/9MYmXlmpSAo/s160-c/Bonzai%252520Rock%252520Sunset.jpg", 

            "https://lh6.googleusercontent.com/-4CN4X4t0M1k/URqufPozWzI/AAAAAAAAAbs/8wK41lg1KPs/s160-c/Caterpillar.jpg", 

            "https://lh3.googleusercontent.com/-rrFnVC8xQEg/URqufdrLBaI/AAAAAAAAAbs/s69WYy_fl1E/s160-c/Chess.jpg", 

            "https://lh5.googleusercontent.com/-WVpRptWH8Yw/URqugh-QmDI/AAAAAAAAAbs/E-MgBgtlUWU/s160-c/Chihuly.jpg", 

            "https://lh5.googleusercontent.com/-0BDXkYmckbo/URquhKFW84I/AAAAAAAAAbs/ogQtHCTk2JQ/s160-c/Closed%252520Door.jpg", 

            "https://lh3.googleusercontent.com/-PyggXXZRykM/URquh-kVvoI/AAAAAAAAAbs/hFtDwhtrHHQ/s160-c/Colorado%252520River%252520Sunset.jpg", 

            "https://lh3.googleusercontent.com/-ZAs4dNZtALc/URquikvOCWI/AAAAAAAAAbs/DXz4h3dll1Y/s160-c/Colors%252520of%252520Autumn.jpg", 

            "https://lh4.googleusercontent.com/-GztnWEIiMz8/URqukVCU7bI/AAAAAAAAAbs/jo2Hjv6MZ6M/s160-c/Countryside.jpg", 

            "https://lh4.googleusercontent.com/-bEg9EZ9QoiM/URquklz3FGI/AAAAAAAAAbs/UUuv8Ac2BaE/s160-c/Death%252520Valley%252520-%252520Dunes.jpg", 

            "https://lh6.googleusercontent.com/-ijQJ8W68tEE/URqulGkvFEI/AAAAAAAAAbs/zPXvIwi_rFw/s160-c/Delicate%252520Arch.jpg", 

            "https://lh5.googleusercontent.com/-Oh8mMy2ieng/URqullDwehI/AAAAAAAAAbs/TbdeEfsaIZY/s160-c/Despair.jpg", 

            "https://lh5.googleusercontent.com/-gl0y4UiAOlk/URqumC_KjBI/AAAAAAAAAbs/PM1eT7dn4oo/s160-c/Eagle%252520Fall%252520Sunrise.jpg", 

            "https://lh3.googleusercontent.com/-hYYHd2_vXPQ/URqumtJa9eI/AAAAAAAAAbs/wAalXVkbSh0/s160-c/Electric%252520Storm.jpg", 

            "https://lh5.googleusercontent.com/-PyY_yiyjPTo/URqunUOhHFI/AAAAAAAAAbs/azZoULNuJXc/s160-c/False%252520Kiva.jpg", 

            "https://lh6.googleusercontent.com/-PYvLVdvXywk/URqunwd8hfI/AAAAAAAAAbs/qiMwgkFvf6I/s160-c/Fitzgerald%252520Streaks.jpg", 

            "https://lh4.googleusercontent.com/-KIR_UobIIqY/URquoCZ9SlI/AAAAAAAAAbs/Y4d4q8sXu4c/s160-c/Foggy%252520Sunset.jpg", 

            "https://lh6.googleusercontent.com/-9lzOk_OWZH0/URquoo4xYoI/AAAAAAAAAbs/AwgzHtNVCwU/s160-c/Frantic.jpg", 

            "https://lh3.googleusercontent.com/-0X3JNaKaz48/URqupH78wpI/AAAAAAAAAbs/lHXxu_zbH8s/s160-c/Golden%252520Gate%252520Afternoon.jpg", 

            "https://lh6.googleusercontent.com/-95sb5ag7ABc/URqupl95RDI/AAAAAAAAAbs/g73R20iVTRA/s160-c/Golden%252520Gate%252520Fog.jpg", 

            "https://lh3.googleusercontent.com/-JB9v6rtgHhk/URqup21F-zI/AAAAAAAAAbs/64Fb8qMZWXk/s160-c/Golden%252520Grass.jpg", 

            "https://lh4.googleusercontent.com/-EIBGfnuLtII/URquqVHwaRI/AAAAAAAAAbs/FA4McV2u8VE/s160-c/Grand%252520Teton.jpg", 

            "https://lh4.googleusercontent.com/-WoMxZvmN9nY/URquq1v2AoI/AAAAAAAAAbs/grj5uMhL6NA/s160-c/Grass%252520Closeup.jpg", 

            "https://lh3.googleusercontent.com/-6hZiEHXx64Q/URqurxvNdqI/AAAAAAAAAbs/kWMXM3o5OVI/s160-c/Green%252520Grass.jpg", 

            "https://lh5.googleusercontent.com/-6LVb9OXtQ60/URquteBFuKI/AAAAAAAAAbs/4F4kRgecwFs/s160-c/Hanging%252520Leaf.jpg", 

            "https://lh4.googleusercontent.com/-zAvf__52ONk/URqutT_IuxI/AAAAAAAAAbs/D_bcuc0thoU/s160-c/Highway%2525201.jpg", 

            "https://lh6.googleusercontent.com/-H4SrUg615rA/URquuL27fXI/AAAAAAAAAbs/4aEqJfiMsOU/s160-c/Horseshoe%252520Bend%252520Sunset.jpg", 

            "https://lh4.googleusercontent.com/-JhFi4fb_Pqw/URquuX-QXbI/AAAAAAAAAbs/IXpYUxuweYM/s160-c/Horseshoe%252520Bend.jpg", 

            "https://lh5.googleusercontent.com/-UGgssvFRJ7g/URquueyJzGI/AAAAAAAAAbs/yYIBlLT0toM/s160-c/Into%252520the%252520Blue.jpg", 

            "https://lh3.googleusercontent.com/-CH7KoupI7uI/URquu0FF__I/AAAAAAAAAbs/R7GDmI7v_G0/s160-c/Jelly%252520Fish%2525202.jpg", 

            "https://lh4.googleusercontent.com/-pwuuw6yhg8U/URquvPxR3FI/AAAAAAAAAbs/VNGk6f-tsGE/s160-c/Jelly%252520Fish%2525203.jpg", 

            "https://lh5.googleusercontent.com/-GoUQVw1fnFw/URquv6xbC0I/AAAAAAAAAbs/zEUVTQQ43Zc/s160-c/Kauai.jpg", 

            "https://lh6.googleusercontent.com/-8QdYYQEpYjw/URquwvdh88I/AAAAAAAAAbs/cktDy-ysfHo/s160-c/Kyoto%252520Sunset.jpg", 

            "https://lh4.googleusercontent.com/-vPeekyDjOE0/URquwzJ28qI/AAAAAAAAAbs/qxcyXULsZrg/s160-c/Lake%252520Tahoe%252520Colors.jpg", 

            "https://lh4.googleusercontent.com/-xBPxWpD4yxU/URquxWHk8AI/AAAAAAAAAbs/ARDPeDYPiMY/s160-c/Lava%252520from%252520the%252520Sky.jpg", 

            "https://lh3.googleusercontent.com/-897VXrJB6RE/URquxxxd-5I/AAAAAAAAAbs/j-Cz4T4YvIw/s160-c/Leica%25252050mm%252520Summilux.jpg", 

            "https://lh5.googleusercontent.com/-qSJ4D4iXzGo/URquyDWiJ1I/AAAAAAAAAbs/k2pBXeWehOA/s160-c/Leica%25252050mm%252520Summilux.jpg", 

            "https://lh6.googleusercontent.com/-dwlPg83vzLg/URquylTVuFI/AAAAAAAAAbs/G6SyQ8b4YsI/s160-c/Leica%252520M8%252520%252528Front%252529.jpg", 

            "https://lh3.googleusercontent.com/-R3_EYAyJvfk/URquzQBv8eI/AAAAAAAAAbs/b9xhpUM3pEI/s160-c/Light%252520to%252520Sand.jpg", 

            "https://lh3.googleusercontent.com/-fHY5h67QPi0/URqu0Cp4J1I/AAAAAAAAAbs/0lG6m94Z6vM/s160-c/Little%252520Bit%252520of%252520Paradise.jpg", 

            "https://lh5.googleusercontent.com/-TzF_LwrCnRM/URqu0RddPOI/AAAAAAAAAbs/gaj2dLiuX0s/s160-c/Lone%252520Pine%252520Sunset.jpg", 

            "https://lh3.googleusercontent.com/-4HdpJ4_DXU4/URqu046dJ9I/AAAAAAAAAbs/eBOodtk2_uk/s160-c/Lonely%252520Rock.jpg", 

            "https://lh6.googleusercontent.com/-erbF--z-W4s/URqu1ajSLkI/AAAAAAAAAbs/xjDCDO1INzM/s160-c/Longue%252520Vue.jpg", 

            "https://lh6.googleusercontent.com/-0CXJRdJaqvc/URqu1opNZNI/AAAAAAAAAbs/PFB2oPUU7Lk/s160-c/Look%252520Me%252520in%252520the%252520Eye.jpg", 

            "https://lh3.googleusercontent.com/-D_5lNxnDN6g/URqu2Tk7HVI/AAAAAAAAAbs/p0ddca9W__Y/s160-c/Lost%252520in%252520a%252520Field.jpg", 

            "https://lh6.googleusercontent.com/-flsqwMrIk2Q/URqu24PcmjI/AAAAAAAAAbs/5ocIH85XofM/s160-c/Marshall%252520Beach%252520Sunset.jpg", 

            "https://lh4.googleusercontent.com/-Y4lgryEVTmU/URqu28kG3gI/AAAAAAAAAbs/OjXpekqtbJ4/s160-c/Mono%252520Lake%252520Blue.jpg", 

            "https://lh4.googleusercontent.com/-AaHAJPmcGYA/URqu3PIldHI/AAAAAAAAAbs/lcTqk1SIcRs/s160-c/Monument%252520Valley%252520Overlook.jpg", 

            "https://lh4.googleusercontent.com/-vKxfdQ83dQA/URqu31Yq_BI/AAAAAAAAAbs/OUoGk_2AyfM/s160-c/Moving%252520Rock.jpg", 

            "https://lh5.googleusercontent.com/-CG62QiPpWXg/URqu4ia4vRI/AAAAAAAAAbs/0YOdqLAlcAc/s160-c/Napali%252520Coast.jpg", 

            "https://lh6.googleusercontent.com/-wdGrP5PMmJQ/URqu5PZvn7I/AAAAAAAAAbs/m0abEcdPXe4/s160-c/One%252520Wheel.jpg", 

            "https://lh6.googleusercontent.com/-6WS5DoCGuOA/URqu5qx1UgI/AAAAAAAAAbs/giMw2ixPvrY/s160-c/Open%252520Sky.jpg", 

            "https://lh6.googleusercontent.com/-u8EHKj8G8GQ/URqu55sM6yI/AAAAAAAAAbs/lIXX_GlTdmI/s160-c/Orange%252520Sunset.jpg", 

            "https://lh6.googleusercontent.com/-74Z5qj4bTDE/URqu6LSrJrI/AAAAAAAAAbs/XzmVkw90szQ/s160-c/Orchid.jpg", 

            "https://lh6.googleusercontent.com/-lEQE4h6TePE/URqu6t_lSkI/AAAAAAAAAbs/zvGYKOea_qY/s160-c/Over%252520there.jpg", 

            "https://lh5.googleusercontent.com/-cauH-53JH2M/URqu66v_USI/AAAAAAAAAbs/EucwwqclfKQ/s160-c/Plumes.jpg", 

            "https://lh3.googleusercontent.com/-eDLT2jHDoy4/URqu7axzkAI/AAAAAAAAAbs/iVZE-xJ7lZs/s160-c/Rainbokeh.jpg", 

            "https://lh5.googleusercontent.com/-j1NLqEFIyco/URqu8L1CGcI/AAAAAAAAAbs/aqZkgX66zlI/s160-c/Rainbow.jpg", 

            "https://lh5.googleusercontent.com/-DRnqmK0t4VU/URqu8XYN9yI/AAAAAAAAAbs/LgvF_592WLU/s160-c/Rice%252520Fields.jpg", 

            "https://lh3.googleusercontent.com/-hwh1v3EOGcQ/URqu8qOaKwI/AAAAAAAAAbs/IljRJRnbJGw/s160-c/Rockaway%252520Fire%252520Sky.jpg", 

            "https://lh5.googleusercontent.com/-wjV6FQk7tlk/URqu9jCQ8sI/AAAAAAAAAbs/RyYUpdo-c9o/s160-c/Rockaway%252520Flow.jpg", 

            "https://lh6.googleusercontent.com/-6cAXNfo7D20/URqu-BdzgPI/AAAAAAAAAbs/OmsYllzJqwo/s160-c/Rockaway%252520Sunset%252520Sky.jpg", 

            "https://lh3.googleusercontent.com/-sl8fpGPS-RE/URqu_BOkfgI/AAAAAAAAAbs/Dg2Fv-JxOeg/s160-c/Russian%252520Ridge%252520Sunset.jpg", 

            "https://lh6.googleusercontent.com/-gVtY36mMBIg/URqu_q91lkI/AAAAAAAAAbs/3CiFMBcy5MA/s160-c/Rust%252520Knot.jpg", 

            "https://lh6.googleusercontent.com/-GHeImuHqJBE/URqu_FKfVLI/AAAAAAAAAbs/axuEJeqam7Q/s160-c/Sailing%252520Stones.jpg", 

            "https://lh3.googleusercontent.com/-hBbYZjTOwGc/URqu_ycpIrI/AAAAAAAAAbs/nAdJUXnGJYE/s160-c/Seahorse.jpg", 

            "https://lh3.googleusercontent.com/-Iwi6-i6IexY/URqvAYZHsVI/AAAAAAAAAbs/5ETWl4qXsFE/s160-c/Shinjuku%252520Street.jpg", 

            "https://lh6.googleusercontent.com/-amhnySTM_MY/URqvAlb5KoI/AAAAAAAAAbs/pFCFgzlKsn0/s160-c/Sierra%252520Heavens.jpg", 

            "https://lh5.googleusercontent.com/-dJgjepFrYSo/URqvBVJZrAI/AAAAAAAAAbs/v-F5QWpYO6s/s160-c/Sierra%252520Sunset.jpg", 

            "https://lh4.googleusercontent.com/-Z4zGiC5nWdc/URqvBdEwivI/AAAAAAAAAbs/ZRZR1VJ84QA/s160-c/Sin%252520Lights.jpg", 

            "https://lh4.googleusercontent.com/-_0cYiWW8ccY/URqvBz3iM4I/AAAAAAAAAbs/9N_Wq8MhLTY/s160-c/Starry%252520Lake.jpg", 

            "https://lh3.googleusercontent.com/-A9LMoRyuQUA/URqvCYx_JoI/AAAAAAAAAbs/s7sde1Bz9cI/s160-c/Starry%252520Night.jpg", 

            "https://lh3.googleusercontent.com/-KtLJ3k858eY/URqvC_2h_bI/AAAAAAAAAbs/zzEBImwDA_g/s160-c/Stream.jpg", 

            "https://lh5.googleusercontent.com/-dFB7Lad6RcA/URqvDUftwWI/AAAAAAAAAbs/BrhoUtXTN7o/s160-c/Strip%252520Sunset.jpg", 

            "https://lh5.googleusercontent.com/-at6apgFiN20/URqvDyffUZI/AAAAAAAAAbs/clABCx171bE/s160-c/Sunset%252520Hills.jpg", 

            "https://lh4.googleusercontent.com/-7-EHhtQthII/URqvEYTk4vI/AAAAAAAAAbs/QSJZoB3YjVg/s160-c/Tenaya%252520Lake%2525202.jpg", 

            "https://lh6.googleusercontent.com/-8MrjV_a-Pok/URqvFC5repI/AAAAAAAAAbs/9inKTg9fbCE/s160-c/Tenaya%252520Lake.jpg", 

            "https://lh5.googleusercontent.com/-B1HW-z4zwao/URqvFWYRwUI/AAAAAAAAAbs/8Peli53Bs8I/s160-c/The%252520Cave%252520BW.jpg", 

            "https://lh3.googleusercontent.com/-PO4E-xZKAnQ/URqvGRqjYkI/AAAAAAAAAbs/42nyADFsXag/s160-c/The%252520Fisherman.jpg", 

            "https://lh4.googleusercontent.com/-iLyZlzfdy7s/URqvG0YScdI/AAAAAAAAAbs/1J9eDKmkXtk/s160-c/The%252520Night%252520is%252520Coming.jpg", 

            "https://lh6.googleusercontent.com/-G-k7YkkUco0/URqvHhah6fI/AAAAAAAAAbs/_taQQG7t0vo/s160-c/The%252520Road.jpg", 

            "https://lh6.googleusercontent.com/-h-ALJt7kSus/URqvIThqYfI/AAAAAAAAAbs/ejiv35olWS8/s160-c/Tokyo%252520Heights.jpg", 

            "https://lh5.googleusercontent.com/-Hy9k-TbS7xg/URqvIjQMOxI/AAAAAAAAAbs/RSpmmOATSkg/s160-c/Tokyo%252520Highway.jpg", 

            "https://lh6.googleusercontent.com/-83oOvMb4OZs/URqvJL0T7lI/AAAAAAAAAbs/c5TECZ6RONM/s160-c/Tokyo%252520Smog.jpg", 

            "https://lh3.googleusercontent.com/-FB-jfgREEfI/URqvJI3EXAI/AAAAAAAAAbs/XfyweiRF4v8/s160-c/Tufa%252520at%252520Night.jpg", 

            "https://lh4.googleusercontent.com/-vngKD5Z1U8w/URqvJUCEgPI/AAAAAAAAAbs/ulxCMVcU6EU/s160-c/Valley%252520Sunset.jpg", 

            "https://lh6.googleusercontent.com/-DOz5I2E2oMQ/URqvKMND1kI/AAAAAAAAAbs/Iqf0IsInleo/s160-c/Windmill%252520Sunrise.jpg", 

            "https://lh5.googleusercontent.com/-biyiyWcJ9MU/URqvKculiAI/AAAAAAAAAbs/jyPsCplJOpE/s160-c/Windmill.jpg", 

            "https://lh4.googleusercontent.com/-PDT167_xRdA/URqvK36mLcI/AAAAAAAAAbs/oi2ik9QseMI/s160-c/Windmills.jpg", 

            "https://lh5.googleusercontent.com/-kI_QdYx7VlU/URqvLXCB6gI/AAAAAAAAAbs/N31vlZ6u89o/s160-c/Yet%252520Another%252520Rockaway%252520Sunset.jpg", 

            "https://lh4.googleusercontent.com/-e9NHZ5k5MSs/URqvMIBZjtI/AAAAAAAAAbs/1fV810rDNfQ/s160-c/Yosemite%252520Tree.jpg", }; 

     
}<span style="font-family: Times New Roman; font-size: 14px;"> 

</span> 

package com.example.asyncimageloader;

public class Images {

public final static String[] imageThumbUrls = new String[] {
"https://lh6.googleusercontent.com/-55osAWw3x0Q/URquUtcFr5I/AAAAAAAAAbs/rWlj1RUKrYI/s160-c/A%252520Photographer.jpg",
"https://lh4.googleusercontent.com/--dq8niRp7W4/URquVgmXvgI/AAAAAAAAAbs/-gnuLQfNnBA/s160-c/A%252520Song%252520of%252520Ice%252520and%252520Fire.jpg",
"https://lh5.googleusercontent.com/-7qZeDtRKFKc/URquWZT1gOI/AAAAAAAAAbs/hqWgteyNXsg/s160-c/Another%252520Rockaway%252520Sunset.jpg",
"https://lh3.googleusercontent.com/--L0Km39l5J8/URquXHGcdNI/AAAAAAAAAbs/3ZrSJNrSomQ/s160-c/Antelope%252520Butte.jpg",
"https://lh6.googleusercontent.com/-8HO-4vIFnlw/URquZnsFgtI/AAAAAAAAAbs/WT8jViTF7vw/s160-c/Antelope%252520Hallway.jpg",
"https://lh4.googleusercontent.com/-WIuWgVcU3Qw/URqubRVcj4I/AAAAAAAAAbs/YvbwgGjwdIQ/s160-c/Antelope%252520Walls.jpg",
"https://lh6.googleusercontent.com/-UBmLbPELvoQ/URqucCdv0kI/AAAAAAAAAbs/IdNhr2VQoQs/s160-c/Apre%2525CC%252580s%252520la%252520Pluie.jpg",
"https://lh3.googleusercontent.com/-s-AFpvgSeew/URquc6dF-JI/AAAAAAAAAbs/Mt3xNGRUd68/s160-c/Backlit%252520Cloud.jpg",
"https://lh5.googleusercontent.com/-bvmif9a9YOQ/URquea3heHI/AAAAAAAAAbs/rcr6wyeQtAo/s160-c/Bee%252520and%252520Flower.jpg",
"https://lh5.googleusercontent.com/-n7mdm7I7FGs/URqueT_BT-I/AAAAAAAAAbs/9MYmXlmpSAo/s160-c/Bonzai%252520Rock%252520Sunset.jpg",
"https://lh6.googleusercontent.com/-4CN4X4t0M1k/URqufPozWzI/AAAAAAAAAbs/8wK41lg1KPs/s160-c/Caterpillar.jpg",
"https://lh3.googleusercontent.com/-rrFnVC8xQEg/URqufdrLBaI/AAAAAAAAAbs/s69WYy_fl1E/s160-c/Chess.jpg",
"https://lh5.googleusercontent.com/-WVpRptWH8Yw/URqugh-QmDI/AAAAAAAAAbs/E-MgBgtlUWU/s160-c/Chihuly.jpg",
"https://lh5.googleusercontent.com/-0BDXkYmckbo/URquhKFW84I/AAAAAAAAAbs/ogQtHCTk2JQ/s160-c/Closed%252520Door.jpg",
"https://lh3.googleusercontent.com/-PyggXXZRykM/URquh-kVvoI/AAAAAAAAAbs/hFtDwhtrHHQ/s160-c/Colorado%252520River%252520Sunset.jpg",
"https://lh3.googleusercontent.com/-ZAs4dNZtALc/URquikvOCWI/AAAAAAAAAbs/DXz4h3dll1Y/s160-c/Colors%252520of%252520Autumn.jpg",
"https://lh4.googleusercontent.com/-GztnWEIiMz8/URqukVCU7bI/AAAAAAAAAbs/jo2Hjv6MZ6M/s160-c/Countryside.jpg",
"https://lh4.googleusercontent.com/-bEg9EZ9QoiM/URquklz3FGI/AAAAAAAAAbs/UUuv8Ac2BaE/s160-c/Death%252520Valley%252520-%252520Dunes.jpg",
"https://lh6.googleusercontent.com/-ijQJ8W68tEE/URqulGkvFEI/AAAAAAAAAbs/zPXvIwi_rFw/s160-c/Delicate%252520Arch.jpg",
"https://lh5.googleusercontent.com/-Oh8mMy2ieng/URqullDwehI/AAAAAAAAAbs/TbdeEfsaIZY/s160-c/Despair.jpg",
"https://lh5.googleusercontent.com/-gl0y4UiAOlk/URqumC_KjBI/AAAAAAAAAbs/PM1eT7dn4oo/s160-c/Eagle%252520Fall%252520Sunrise.jpg",
"https://lh3.googleusercontent.com/-hYYHd2_vXPQ/URqumtJa9eI/AAAAAAAAAbs/wAalXVkbSh0/s160-c/Electric%252520Storm.jpg",
"https://lh5.googleusercontent.com/-PyY_yiyjPTo/URqunUOhHFI/AAAAAAAAAbs/azZoULNuJXc/s160-c/False%252520Kiva.jpg",
"https://lh6.googleusercontent.com/-PYvLVdvXywk/URqunwd8hfI/AAAAAAAAAbs/qiMwgkFvf6I/s160-c/Fitzgerald%252520Streaks.jpg",
"https://lh4.googleusercontent.com/-KIR_UobIIqY/URquoCZ9SlI/AAAAAAAAAbs/Y4d4q8sXu4c/s160-c/Foggy%252520Sunset.jpg",
"https://lh6.googleusercontent.com/-9lzOk_OWZH0/URquoo4xYoI/AAAAAAAAAbs/AwgzHtNVCwU/s160-c/Frantic.jpg",
"https://lh3.googleusercontent.com/-0X3JNaKaz48/URqupH78wpI/AAAAAAAAAbs/lHXxu_zbH8s/s160-c/Golden%252520Gate%252520Afternoon.jpg",
"https://lh6.googleusercontent.com/-95sb5ag7ABc/URqupl95RDI/AAAAAAAAAbs/g73R20iVTRA/s160-c/Golden%252520Gate%252520Fog.jpg",
"https://lh3.googleusercontent.com/-JB9v6rtgHhk/URqup21F-zI/AAAAAAAAAbs/64Fb8qMZWXk/s160-c/Golden%252520Grass.jpg",
"https://lh4.googleusercontent.com/-EIBGfnuLtII/URquqVHwaRI/AAAAAAAAAbs/FA4McV2u8VE/s160-c/Grand%252520Teton.jpg",
"https://lh4.googleusercontent.com/-WoMxZvmN9nY/URquq1v2AoI/AAAAAAAAAbs/grj5uMhL6NA/s160-c/Grass%252520Closeup.jpg",
"https://lh3.googleusercontent.com/-6hZiEHXx64Q/URqurxvNdqI/AAAAAAAAAbs/kWMXM3o5OVI/s160-c/Green%252520Grass.jpg",
"https://lh5.googleusercontent.com/-6LVb9OXtQ60/URquteBFuKI/AAAAAAAAAbs/4F4kRgecwFs/s160-c/Hanging%252520Leaf.jpg",
"https://lh4.googleusercontent.com/-zAvf__52ONk/URqutT_IuxI/AAAAAAAAAbs/D_bcuc0thoU/s160-c/Highway%2525201.jpg",
"https://lh6.googleusercontent.com/-H4SrUg615rA/URquuL27fXI/AAAAAAAAAbs/4aEqJfiMsOU/s160-c/Horseshoe%252520Bend%252520Sunset.jpg",
"https://lh4.googleusercontent.com/-JhFi4fb_Pqw/URquuX-QXbI/AAAAAAAAAbs/IXpYUxuweYM/s160-c/Horseshoe%252520Bend.jpg",
"https://lh5.googleusercontent.com/-UGgssvFRJ7g/URquueyJzGI/AAAAAAAAAbs/yYIBlLT0toM/s160-c/Into%252520the%252520Blue.jpg",
"https://lh3.googleusercontent.com/-CH7KoupI7uI/URquu0FF__I/AAAAAAAAAbs/R7GDmI7v_G0/s160-c/Jelly%252520Fish%2525202.jpg",
"https://lh4.googleusercontent.com/-pwuuw6yhg8U/URquvPxR3FI/AAAAAAAAAbs/VNGk6f-tsGE/s160-c/Jelly%252520Fish%2525203.jpg",
"https://lh5.googleusercontent.com/-GoUQVw1fnFw/URquv6xbC0I/AAAAAAAAAbs/zEUVTQQ43Zc/s160-c/Kauai.jpg",
"https://lh6.googleusercontent.com/-8QdYYQEpYjw/URquwvdh88I/AAAAAAAAAbs/cktDy-ysfHo/s160-c/Kyoto%252520Sunset.jpg",
"https://lh4.googleusercontent.com/-vPeekyDjOE0/URquwzJ28qI/AAAAAAAAAbs/qxcyXULsZrg/s160-c/Lake%252520Tahoe%252520Colors.jpg",
"https://lh4.googleusercontent.com/-xBPxWpD4yxU/URquxWHk8AI/AAAAAAAAAbs/ARDPeDYPiMY/s160-c/Lava%252520from%252520the%252520Sky.jpg",
"https://lh3.googleusercontent.com/-897VXrJB6RE/URquxxxd-5I/AAAAAAAAAbs/j-Cz4T4YvIw/s160-c/Leica%25252050mm%252520Summilux.jpg",
"https://lh5.googleusercontent.com/-qSJ4D4iXzGo/URquyDWiJ1I/AAAAAAAAAbs/k2pBXeWehOA/s160-c/Leica%25252050mm%252520Summilux.jpg",
"https://lh6.googleusercontent.com/-dwlPg83vzLg/URquylTVuFI/AAAAAAAAAbs/G6SyQ8b4YsI/s160-c/Leica%252520M8%252520%252528Front%252529.jpg",
"https://lh3.googleusercontent.com/-R3_EYAyJvfk/URquzQBv8eI/AAAAAAAAAbs/b9xhpUM3pEI/s160-c/Light%252520to%252520Sand.jpg",
"https://lh3.googleusercontent.com/-fHY5h67QPi0/URqu0Cp4J1I/AAAAAAAAAbs/0lG6m94Z6vM/s160-c/Little%252520Bit%252520of%252520Paradise.jpg",
"https://lh5.googleusercontent.com/-TzF_LwrCnRM/URqu0RddPOI/AAAAAAAAAbs/gaj2dLiuX0s/s160-c/Lone%252520Pine%252520Sunset.jpg",
"https://lh3.googleusercontent.com/-4HdpJ4_DXU4/URqu046dJ9I/AAAAAAAAAbs/eBOodtk2_uk/s160-c/Lonely%252520Rock.jpg",
"https://lh6.googleusercontent.com/-erbF--z-W4s/URqu1ajSLkI/AAAAAAAAAbs/xjDCDO1INzM/s160-c/Longue%252520Vue.jpg",
"https://lh6.googleusercontent.com/-0CXJRdJaqvc/URqu1opNZNI/AAAAAAAAAbs/PFB2oPUU7Lk/s160-c/Look%252520Me%252520in%252520the%252520Eye.jpg",
"https://lh3.googleusercontent.com/-D_5lNxnDN6g/URqu2Tk7HVI/AAAAAAAAAbs/p0ddca9W__Y/s160-c/Lost%252520in%252520a%252520Field.jpg",
"https://lh6.googleusercontent.com/-flsqwMrIk2Q/URqu24PcmjI/AAAAAAAAAbs/5ocIH85XofM/s160-c/Marshall%252520Beach%252520Sunset.jpg",
"https://lh4.googleusercontent.com/-Y4lgryEVTmU/URqu28kG3gI/AAAAAAAAAbs/OjXpekqtbJ4/s160-c/Mono%252520Lake%252520Blue.jpg",
"https://lh4.googleusercontent.com/-AaHAJPmcGYA/URqu3PIldHI/AAAAAAAAAbs/lcTqk1SIcRs/s160-c/Monument%252520Valley%252520Overlook.jpg",
"https://lh4.googleusercontent.com/-vKxfdQ83dQA/URqu31Yq_BI/AAAAAAAAAbs/OUoGk_2AyfM/s160-c/Moving%252520Rock.jpg",
"https://lh5.googleusercontent.com/-CG62QiPpWXg/URqu4ia4vRI/AAAAAAAAAbs/0YOdqLAlcAc/s160-c/Napali%252520Coast.jpg",
"https://lh6.googleusercontent.com/-wdGrP5PMmJQ/URqu5PZvn7I/AAAAAAAAAbs/m0abEcdPXe4/s160-c/One%252520Wheel.jpg",
"https://lh6.googleusercontent.com/-6WS5DoCGuOA/URqu5qx1UgI/AAAAAAAAAbs/giMw2ixPvrY/s160-c/Open%252520Sky.jpg",
"https://lh6.googleusercontent.com/-u8EHKj8G8GQ/URqu55sM6yI/AAAAAAAAAbs/lIXX_GlTdmI/s160-c/Orange%252520Sunset.jpg",
"https://lh6.googleusercontent.com/-74Z5qj4bTDE/URqu6LSrJrI/AAAAAAAAAbs/XzmVkw90szQ/s160-c/Orchid.jpg",
"https://lh6.googleusercontent.com/-lEQE4h6TePE/URqu6t_lSkI/AAAAAAAAAbs/zvGYKOea_qY/s160-c/Over%252520there.jpg",
"https://lh5.googleusercontent.com/-cauH-53JH2M/URqu66v_USI/AAAAAAAAAbs/EucwwqclfKQ/s160-c/Plumes.jpg",
"https://lh3.googleusercontent.com/-eDLT2jHDoy4/URqu7axzkAI/AAAAAAAAAbs/iVZE-xJ7lZs/s160-c/Rainbokeh.jpg",
"https://lh5.googleusercontent.com/-j1NLqEFIyco/URqu8L1CGcI/AAAAAAAAAbs/aqZkgX66zlI/s160-c/Rainbow.jpg",
"https://lh5.googleusercontent.com/-DRnqmK0t4VU/URqu8XYN9yI/AAAAAAAAAbs/LgvF_592WLU/s160-c/Rice%252520Fields.jpg",
"https://lh3.googleusercontent.com/-hwh1v3EOGcQ/URqu8qOaKwI/AAAAAAAAAbs/IljRJRnbJGw/s160-c/Rockaway%252520Fire%252520Sky.jpg",
"https://lh5.googleusercontent.com/-wjV6FQk7tlk/URqu9jCQ8sI/AAAAAAAAAbs/RyYUpdo-c9o/s160-c/Rockaway%252520Flow.jpg",
"https://lh6.googleusercontent.com/-6cAXNfo7D20/URqu-BdzgPI/AAAAAAAAAbs/OmsYllzJqwo/s160-c/Rockaway%252520Sunset%252520Sky.jpg",
"https://lh3.googleusercontent.com/-sl8fpGPS-RE/URqu_BOkfgI/AAAAAAAAAbs/Dg2Fv-JxOeg/s160-c/Russian%252520Ridge%252520Sunset.jpg",
"https://lh6.googleusercontent.com/-gVtY36mMBIg/URqu_q91lkI/AAAAAAAAAbs/3CiFMBcy5MA/s160-c/Rust%252520Knot.jpg",
"https://lh6.googleusercontent.com/-GHeImuHqJBE/URqu_FKfVLI/AAAAAAAAAbs/axuEJeqam7Q/s160-c/Sailing%252520Stones.jpg",
"https://lh3.googleusercontent.com/-hBbYZjTOwGc/URqu_ycpIrI/AAAAAAAAAbs/nAdJUXnGJYE/s160-c/Seahorse.jpg",
"https://lh3.googleusercontent.com/-Iwi6-i6IexY/URqvAYZHsVI/AAAAAAAAAbs/5ETWl4qXsFE/s160-c/Shinjuku%252520Street.jpg",
"https://lh6.googleusercontent.com/-amhnySTM_MY/URqvAlb5KoI/AAAAAAAAAbs/pFCFgzlKsn0/s160-c/Sierra%252520Heavens.jpg",
"https://lh5.googleusercontent.com/-dJgjepFrYSo/URqvBVJZrAI/AAAAAAAAAbs/v-F5QWpYO6s/s160-c/Sierra%252520Sunset.jpg",
"https://lh4.googleusercontent.com/-Z4zGiC5nWdc/URqvBdEwivI/AAAAAAAAAbs/ZRZR1VJ84QA/s160-c/Sin%252520Lights.jpg",
"https://lh4.googleusercontent.com/-_0cYiWW8ccY/URqvBz3iM4I/AAAAAAAAAbs/9N_Wq8MhLTY/s160-c/Starry%252520Lake.jpg",
"https://lh3.googleusercontent.com/-A9LMoRyuQUA/URqvCYx_JoI/AAAAAAAAAbs/s7sde1Bz9cI/s160-c/Starry%252520Night.jpg",
"https://lh3.googleusercontent.com/-KtLJ3k858eY/URqvC_2h_bI/AAAAAAAAAbs/zzEBImwDA_g/s160-c/Stream.jpg",
"https://lh5.googleusercontent.com/-dFB7Lad6RcA/URqvDUftwWI/AAAAAAAAAbs/BrhoUtXTN7o/s160-c/Strip%252520Sunset.jpg",
"https://lh5.googleusercontent.com/-at6apgFiN20/URqvDyffUZI/AAAAAAAAAbs/clABCx171bE/s160-c/Sunset%252520Hills.jpg",
"https://lh4.googleusercontent.com/-7-EHhtQthII/URqvEYTk4vI/AAAAAAAAAbs/QSJZoB3YjVg/s160-c/Tenaya%252520Lake%2525202.jpg",
"https://lh6.googleusercontent.com/-8MrjV_a-Pok/URqvFC5repI/AAAAAAAAAbs/9inKTg9fbCE/s160-c/Tenaya%252520Lake.jpg",
"https://lh5.googleusercontent.com/-B1HW-z4zwao/URqvFWYRwUI/AAAAAAAAAbs/8Peli53Bs8I/s160-c/The%252520Cave%252520BW.jpg",
"https://lh3.googleusercontent.com/-PO4E-xZKAnQ/URqvGRqjYkI/AAAAAAAAAbs/42nyADFsXag/s160-c/The%252520Fisherman.jpg",
"https://lh4.googleusercontent.com/-iLyZlzfdy7s/URqvG0YScdI/AAAAAAAAAbs/1J9eDKmkXtk/s160-c/The%252520Night%252520is%252520Coming.jpg",
"https://lh6.googleusercontent.com/-G-k7YkkUco0/URqvHhah6fI/AAAAAAAAAbs/_taQQG7t0vo/s160-c/The%252520Road.jpg",
"https://lh6.googleusercontent.com/-h-ALJt7kSus/URqvIThqYfI/AAAAAAAAAbs/ejiv35olWS8/s160-c/Tokyo%252520Heights.jpg",
"https://lh5.googleusercontent.com/-Hy9k-TbS7xg/URqvIjQMOxI/AAAAAAAAAbs/RSpmmOATSkg/s160-c/Tokyo%252520Highway.jpg",
"https://lh6.googleusercontent.com/-83oOvMb4OZs/URqvJL0T7lI/AAAAAAAAAbs/c5TECZ6RONM/s160-c/Tokyo%252520Smog.jpg",
"https://lh3.googleusercontent.com/-FB-jfgREEfI/URqvJI3EXAI/AAAAAAAAAbs/XfyweiRF4v8/s160-c/Tufa%252520at%252520Night.jpg",
"https://lh4.googleusercontent.com/-vngKD5Z1U8w/URqvJUCEgPI/AAAAAAAAAbs/ulxCMVcU6EU/s160-c/Valley%252520Sunset.jpg",
"https://lh6.googleusercontent.com/-DOz5I2E2oMQ/URqvKMND1kI/AAAAAAAAAbs/Iqf0IsInleo/s160-c/Windmill%252520Sunrise.jpg",
"https://lh5.googleusercontent.com/-biyiyWcJ9MU/URqvKculiAI/AAAAAAAAAbs/jyPsCplJOpE/s160-c/Windmill.jpg",
"https://lh4.googleusercontent.com/-PDT167_xRdA/URqvK36mLcI/AAAAAAAAAbs/oi2ik9QseMI/s160-c/Windmills.jpg",
"https://lh5.googleusercontent.com/-kI_QdYx7VlU/URqvLXCB6gI/AAAAAAAAAbs/N31vlZ6u89o/s160-c/Yet%252520Another%252520Rockaway%252520Sunset.jpg",
"https://lh4.googleusercontent.com/-e9NHZ5k5MSs/URqvMIBZjtI/AAAAAAAAAbs/1fV810rDNfQ/s160-c/Yosemite%252520Tree.jpg", };

}<span style="font-family:Times New Roman;font-size:14px;">
</span>


ImageDownLoader类，异步下载的核心类，保存图片到手机缓存，将图片加入LruCache中等等

[java]
view plaincopyprint?





package com.example.asyncimageloader; 

 
import java.io.IOException; 

import java.net.HttpURLConnection; 

import java.net.URL; 

import java.util.concurrent.ExecutorService; 

import java.util.concurrent.Executors; 

 
import android.content.Context; 

import android.graphics.Bitmap; 

import android.graphics.BitmapFactory; 

import android.os.Handler; 
import android.os.Message; 

import android.support.v4.util.LruCache; 

 
public class ImageDownLoader { 

    /**
     * 缓存Image的类，当存储Image的大小大于LruCache设定的值，系统自动释放内存

     */ 
    private LruCache<String, Bitmap> mMemoryCache; 

    /**
     * 操作文件相关类对象的引用
     */ 
    private FileUtils fileUtils; 

    /**
     * 下载Image的线程池
     */ 
    private ExecutorService mImageThreadPool =
null; 
     
     
    public ImageDownLoader(Context context){ 

        //获取系统分配给每个应用程序的最大内存，每个应用系统分配32M 

        int maxMemory = (int) Runtime.getRuntime().maxMemory();   

        int mCacheSize = maxMemory /
8; 
        //给LruCache分配1/8 4M 

        mMemoryCache = new LruCache<String, Bitmap>(mCacheSize){ 

 
            //必须重写此方法，来测量Bitmap的大小 

            @Override 

            protected int sizeOf(String key, Bitmap value) { 

                return value.getRowBytes() * value.getHeight(); 

            } 
             
        }; 
         
        fileUtils = new FileUtils(context); 

    } 
     
     
    /**
     * 获取线程池的方法，因为涉及到并发的问题，我们加上同步锁

     * @return
     */ 
    public ExecutorService getThreadPool(){ 

        if(mImageThreadPool ==
null){ 
            synchronized(ExecutorService.class){ 

                if(mImageThreadPool ==
null){ 
                    //为了下载图片更加的流畅，我们用了2个线程来下载图片 

                    mImageThreadPool = Executors.newFixedThreadPool(2); 

                } 
            } 
        } 
         
        return mImageThreadPool; 

         
    } 
     
    /**
     * 添加Bitmap到内存缓存
     * @param key
     * @param bitmap
     */ 
    public void addBitmapToMemoryCache(String key, Bitmap bitmap) {   

        if (getBitmapFromMemCache(key) ==
null && bitmap != null) {   

            mMemoryCache.put(key, bitmap);   
        }   
    }   
      
    /**
     * 从内存缓存中获取一个Bitmap
     * @param key
     * @return
     */ 
    public Bitmap getBitmapFromMemCache(String key) {   

        return mMemoryCache.get(key);   

    }  
     
    /**
     * 先从内存缓存中获取Bitmap,如果没有就从SD卡或者手机缓存中获取，SD卡或者手机缓存

     * 没有就去下载
     * @param url
     * @param listener
     * @return
     */ 
    public Bitmap downloadImage(final String url,
final onImageLoaderListener listener){ 

        //替换Url中非字母和非数字的字符，这里比较重要，因为我们用Url作为文件名，比如我们的Url 

        //是Http://xiaanming/abc.jpg;用这个作为图片名称，系统会认为xiaanming为一个目录， 

        //我们没有创建此目录保存文件就会报错 

        final String subUrl = url.replaceAll("[^\\w]",
""); 
        Bitmap bitmap = showCacheBitmap(subUrl); 
        if(bitmap !=
null){ 
            return bitmap; 
        }else{ 
             
            final Handler handler =
new Handler(){ 
                @Override 

                public
void handleMessage(Message msg) { 
                    super.handleMessage(msg); 

                    listener.onImageLoader((Bitmap)msg.obj, url); 

                } 
            }; 
             
            getThreadPool().execute(new Runnable() { 

                 
                @Override 

                public void run() { 

                    Bitmap bitmap = getBitmapFormUrl(url); 

                    Message msg = handler.obtainMessage(); 
                    msg.obj = bitmap; 
                    handler.sendMessage(msg); 
                     
                    try { 
                        //保存在SD卡或者手机目录 

                        fileUtils.savaBitmap(subUrl, bitmap); 
                    } catch (IOException e) { 

                        e.printStackTrace(); 
                    } 
                     
                    //将Bitmap 加入内存缓存 

                    addBitmapToMemoryCache(subUrl, bitmap); 
                } 
            }); 
        } 
         
        return null; 

    } 
     
    /**
     * 获取Bitmap, 内存中没有就去手机或者sd卡中获取，这一步在getView中会调用，比较关键的一步

     * @param url
     * @return
     */ 
    public Bitmap showCacheBitmap(String url){ 

        if(getBitmapFromMemCache(url) !=
null){ 
            return getBitmapFromMemCache(url); 

        }else if(fileUtils.isFileExists(url) && fileUtils.getFileSize(url) !=
0){ 
            //从SD卡获取手机里面获取Bitmap 

            Bitmap bitmap = fileUtils.getBitmap(url); 
             
            //将Bitmap 加入内存缓存 

            addBitmapToMemoryCache(url, bitmap); 
            return bitmap; 
        } 
         
        return null; 

    } 
     
     
    /**
     * 从Url中获取Bitmap
     * @param url
     * @return
     */ 
    private Bitmap getBitmapFormUrl(String url) { 

        Bitmap bitmap = null; 

        HttpURLConnection con = null; 

        try { 
            URL mImageUrl = new URL(url); 

            con = (HttpURLConnection) mImageUrl.openConnection(); 

            con.setConnectTimeout(10 *
1000); 
            con.setReadTimeout(10 *
1000); 
            con.setDoInput(true); 

            con.setDoOutput(true); 

            bitmap = BitmapFactory.decodeStream(con.getInputStream()); 

        } catch (Exception e) { 

            e.printStackTrace(); 
        } finally { 

            if (con != null) { 

                con.disconnect(); 
            } 
        } 
        return bitmap; 
    } 
     
    /**
     * 取消正在下载的任务
     */ 
    public synchronized
void cancelTask() { 
        if(mImageThreadPool !=
null){ 
            mImageThreadPool.shutdownNow(); 
            mImageThreadPool = null; 

        } 
    } 
     
     
    /**
     * 异步下载图片的回调接口
     * @author len
     *
     */ 
    public interface onImageLoaderListener{ 

        void onImageLoader(Bitmap bitmap, String url); 

    } 
     
} 

package com.example.asyncimageloader;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;
import android.support.v4.util.LruCache;

public class ImageDownLoader {
/**
* 缓存Image的类，当存储Image的大小大于LruCache设定的值，系统自动释放内存
*/
private LruCache<String, Bitmap> mMemoryCache;
/**
* 操作文件相关类对象的引用
*/
private FileUtils fileUtils;
/**
* 下载Image的线程池
*/
private ExecutorService mImageThreadPool = null;

public ImageDownLoader(Context context){
//获取系统分配给每个应用程序的最大内存，每个应用系统分配32M
int maxMemory = (int) Runtime.getRuntime().maxMemory();
int mCacheSize = maxMemory / 8;
//给LruCache分配1/8 4M
mMemoryCache = new LruCache<String, Bitmap>(mCacheSize){

//必须重写此方法，来测量Bitmap的大小
@Override
protected int sizeOf(String key, Bitmap value) {
return value.getRowBytes() * value.getHeight();
}

};

fileUtils = new FileUtils(context);
}

/**
* 获取线程池的方法，因为涉及到并发的问题，我们加上同步锁
* @return
*/
public ExecutorService getThreadPool(){
if(mImageThreadPool == null){
synchronized(ExecutorService.class){
if(mImageThreadPool == null){
//为了下载图片更加的流畅，我们用了2个线程来下载图片
mImageThreadPool = Executors.newFixedThreadPool(2);
}
}
}

return mImageThreadPool;

}

/**
* 添加Bitmap到内存缓存
* @param key
* @param bitmap
*/
public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null && bitmap != null) {
mMemoryCache.put(key, bitmap);
}
}

/**
* 从内存缓存中获取一个Bitmap
* @param key
* @return
*/
public Bitmap getBitmapFromMemCache(String key) {
return mMemoryCache.get(key);
}

/**
* 先从内存缓存中获取Bitmap,如果没有就从SD卡或者手机缓存中获取，SD卡或者手机缓存
* 没有就去下载
* @param url
* @param listener
* @return
*/
public Bitmap downloadImage(final String url, final onImageLoaderListener listener){
//替换Url中非字母和非数字的字符，这里比较重要，因为我们用Url作为文件名，比如我们的Url
//是Http://xiaanming/abc.jpg;用这个作为图片名称，系统会认为xiaanming为一个目录，
//我们没有创建此目录保存文件就会报错
final String subUrl = url.replaceAll("[^\\w]", "");
Bitmap bitmap = showCacheBitmap(subUrl);
if(bitmap != null){
return bitmap;
}else{

final Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
listener.onImageLoader((Bitmap)msg.obj, url);
}
};

getThreadPool().execute(new Runnable() {

@Override
public void run() {
Bitmap bitmap = getBitmapFormUrl(url);
Message msg = handler.obtainMessage();
msg.obj = bitmap;
handler.sendMessage(msg);

try {
//保存在SD卡或者手机目录
fileUtils.savaBitmap(subUrl, bitmap);
} catch (IOException e) {
e.printStackTrace();
}

//将Bitmap 加入内存缓存
addBitmapToMemoryCache(subUrl, bitmap);
}
});
}

return null;
}

/**
* 获取Bitmap, 内存中没有就去手机或者sd卡中获取，这一步在getView中会调用，比较关键的一步
* @param url
* @return
*/
public Bitmap showCacheBitmap(String url){
if(getBitmapFromMemCache(url) != null){
return getBitmapFromMemCache(url);
}else if(fileUtils.isFileExists(url) && fileUtils.getFileSize(url) != 0){
//从SD卡获取手机里面获取Bitmap
Bitmap bitmap = fileUtils.getBitmap(url);

//将Bitmap 加入内存缓存
addBitmapToMemoryCache(url, bitmap);
return bitmap;
}

return null;
}

/**
* 从Url中获取Bitmap
* @param url
* @return
*/
private Bitmap getBitmapFormUrl(String url) {
Bitmap bitmap = null;
HttpURLConnection con = null;
try {
URL mImageUrl = new URL(url);
con = (HttpURLConnection) mImageUrl.openConnection();
con.setConnectTimeout(10 * 1000);
con.setReadTimeout(10 * 1000);
con.setDoInput(true);
con.setDoOutput(true);
bitmap = BitmapFactory.decodeStream(con.getInputStream());
} catch (Exception e) {
e.printStackTrace();
} finally {
if (con != null) {
con.disconnect();
}
}
return bitmap;
}

/**
* 取消正在下载的任务
*/
public synchronized void cancelTask() {
if(mImageThreadPool != null){
mImageThreadPool.shutdownNow();
mImageThreadPool = null;
}
}

/**
* 异步下载图片的回调接口
* @author len
*
*/
public interface onImageLoaderListener{
void onImageLoader(Bitmap bitmap, String url);
}

}
ImageDownLoader中有几个方法比较重要

首先我们需要重写sizeOf(String key, Bitmap value)来计算图片的大小，默认返回图片的数量
downloadImage(final String url, final onImageLoaderListener listener)先去LruCache查看Image,没有再去手机缓存中查看，在没有则开启线程下载，这里我们提供了一个回调接口，回调方法中我们将Bitmap和图片Url作为参数，String subUrl = url.replaceAll("[^\\w]", "") 我在代码中注释写的比较清楚
showCacheBitmap(String url)方法，此方法在Adapter中的getView()当中调用，如果getView()中不调用此方法试试你就知道效果了

ImageAdapter  GridView的适配器类，主要是GridView滑动的时候取消下载任务，静止的时候去下载当前显示的item的图片，其他也没什么不同了

[java]
view plaincopyprint?





package com.example.asyncimageloader; 

 
import android.content.Context; 

import android.graphics.Bitmap; 

import android.view.View; 

import android.view.ViewGroup; 

import android.widget.AbsListView; 

import android.widget.AbsListView.OnScrollListener; 

import android.widget.BaseAdapter; 

import android.widget.GridView; 

import android.widget.ImageView; 

 
import com.example.asyncimageloader.ImageDownLoader.onImageLoaderListener; 

 
public class ImageAdapter
extends BaseAdapter implements OnScrollListener{ 

    /**
     * 上下文对象的引用
     */ 
    private Context context; 

     
    /**
     * Image Url的数组
     */ 
    private String [] imageThumbUrls; 

     
    /**
     * GridView对象的应用
     */ 
    private GridView mGridView; 

     
    /**
     * Image 下载器
     */ 
    private ImageDownLoader mImageDownLoader; 

     
    /**
     * 记录是否刚打开程序，用于解决进入程序不滚动屏幕，不会下载图片的问题。

     * 参考http://blog.csdn.net/guolin_blog/article/details/9526203#comments

     */ 
    private boolean isFirstEnter =
true; 
     
    /**
     * 一屏中第一个item的位置
     */ 
    private int mFirstVisibleItem; 

     
    /**
     * 一屏中所有item的个数
     */ 
    private int mVisibleItemCount; 

     
     
    public ImageAdapter(Context context, GridView mGridView, String [] imageThumbUrls){ 

        this.context = context; 

        this.mGridView = mGridView; 

        this.imageThumbUrls = imageThumbUrls; 

        mImageDownLoader = new ImageDownLoader(context); 

        mGridView.setOnScrollListener(this); 

    } 
     
    @Override 

    public void onScrollStateChanged(AbsListView view,
int scrollState) { 
        //仅当GridView静止时才去下载图片，GridView滑动时取消所有正在下载的任务 
 
        if(scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE){ 

            showImage(mFirstVisibleItem, mVisibleItemCount); 

        }else{ 
            cancelTask(); 
        } 
         
    } 
 
 
    /**
     * GridView滚动的时候调用的方法，刚开始显示GridView也会调用此方法

     */ 
    @Override 
    public void onScroll(AbsListView view,
int firstVisibleItem, 
            int visibleItemCount,
int totalItemCount) { 
        mFirstVisibleItem = firstVisibleItem; 
        mVisibleItemCount = visibleItemCount; 
        // 因此在这里为首次进入程序开启下载任务。
 
        if(isFirstEnter && visibleItemCount >
0){ 
            showImage(mFirstVisibleItem, mVisibleItemCount); 

            isFirstEnter = false; 

        } 
    } 
     
 
    @Override 

    public int getCount() { 

        return imageThumbUrls.length; 

    } 
 
    @Override 
    public Object getItem(int position) { 

        return imageThumbUrls[position]; 

    } 
 
    @Override 

    public long getItemId(int position) { 

        return position; 

    } 
 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 

        ImageView mImageView; 
        final String mImageUrl = imageThumbUrls[position]; 

        if(convertView == null){ 

            mImageView = new ImageView(context); 

        }else{ 
            mImageView = (ImageView) convertView; 
        } 
         
        mImageView.setLayoutParams(new GridView.LayoutParams(150,
150)); 
        mImageView.setScaleType(ImageView.ScaleType.CENTER_INSIDE); 

         
        //给ImageView设置Tag,这里已经是司空见惯了 

        mImageView.setTag(mImageUrl); 
         
         
        /*******************************去掉下面这几行试试是什么效果****************************/ 

        Bitmap bitmap = mImageDownLoader.showCacheBitmap(mImageUrl.replaceAll("[^\\w]",
"")); 
        if(bitmap !=
null){ 
            mImageView.setImageBitmap(bitmap); 
        }else{ 
            mImageView.setImageDrawable(context.getResources().getDrawable(R.drawable.ic_empty)); 

        } 
        /**********************************************************************************/ 

         
         
        return mImageView; 

    } 
     
    /**
     * 显示当前屏幕的图片，先会去查找LruCache，LruCache没有就去sd卡或者手机目录查找，在没有就开启线程去下载

     * @param firstVisibleItem
     * @param visibleItemCount

     */ 
    private void showImage(int firstVisibleItem,
int visibleItemCount){ 
        Bitmap bitmap = null; 

        for(int i=firstVisibleItem; i<firstVisibleItem + visibleItemCount; i++){ 

            String mImageUrl = imageThumbUrls[i]; 
            final ImageView mImageView = (ImageView) mGridView.findViewWithTag(mImageUrl); 

            bitmap = mImageDownLoader.downloadImage(mImageUrl,
new onImageLoaderListener() { 
                 
                @Override 

                public
void onImageLoader(Bitmap bitmap, String url) { 

                    if(mImageView !=
null && bitmap != null){ 

                        mImageView.setImageBitmap(bitmap); 

                    } 
                     
                } 
            }); 
             
            //if(bitmap != null){ 

            //  mImageView.setImageBitmap(bitmap); 

            //}else{ 

            //  mImageView.setImageDrawable(context.getResources().getDrawable(R.drawable.ic_empty)); 

            //} 

        } 
    } 
 
    /**
     * 取消下载任务
     */ 
    public void cancelTask(){ 

        mImageDownLoader.cancelTask(); 
    } 
 
 
} 

package com.example.asyncimageloader;

import android.content.Context;
import android.graphics.Bitmap;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

import com.example.asyncimageloader.ImageDownLoader.onImageLoaderListener;

public class ImageAdapter extends BaseAdapter implements OnScrollListener{
/**
* 上下文对象的引用
*/
private Context context;

/**
* Image Url的数组
*/
private String [] imageThumbUrls;

/**
* GridView对象的应用
*/
private GridView mGridView;

/**
* Image 下载器
*/
private ImageDownLoader mImageDownLoader;

/**
* 记录是否刚打开程序，用于解决进入程序不滚动屏幕，不会下载图片的问题。
* 参考http://blog.csdn.net/guolin_blog/article/details/9526203#comments
*/
private boolean isFirstEnter = true;

/**
* 一屏中第一个item的位置
*/
private int mFirstVisibleItem;

/**
* 一屏中所有item的个数
*/
private int mVisibleItemCount;

public ImageAdapter(Context context, GridView mGridView, String [] imageThumbUrls){
this.context = context;
this.mGridView = mGridView;
this.imageThumbUrls = imageThumbUrls;
mImageDownLoader = new ImageDownLoader(context);
mGridView.setOnScrollListener(this);
}

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
//仅当GridView静止时才去下载图片，GridView滑动时取消所有正在下载的任务
if(scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE){
showImage(mFirstVisibleItem, mVisibleItemCount);
}else{
cancelTask();
}

}

/**
* GridView滚动的时候调用的方法，刚开始显示GridView也会调用此方法
*/
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
mFirstVisibleItem = firstVisibleItem;
mVisibleItemCount = visibleItemCount;
// 因此在这里为首次进入程序开启下载任务。
if(isFirstEnter && visibleItemCount > 0){
showImage(mFirstVisibleItem, mVisibleItemCount);
isFirstEnter = false;
}
}

@Override
public int getCount() {
return imageThumbUrls.length;
}

@Override
public Object getItem(int position) {
return imageThumbUrls[position];
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView mImageView;
final String mImageUrl = imageThumbUrls[position];
if(convertView == null){
mImageView = new ImageView(context);
}else{
mImageView = (ImageView) convertView;
}

mImageView.setLayoutParams(new GridView.LayoutParams(150, 150));
mImageView.setScaleType(ImageView.ScaleType.CENTER_INSIDE);

//给ImageView设置Tag,这里已经是司空见惯了
mImageView.setTag(mImageUrl);

/*******************************去掉下面这几行试试是什么效果****************************/
Bitmap bitmap = mImageDownLoader.showCacheBitmap(mImageUrl.replaceAll("[^\\w]", ""));
if(bitmap != null){
mImageView.setImageBitmap(bitmap);
}else{
mImageView.setImageDrawable(context.getResources().getDrawable(R.drawable.ic_empty));
}
/**********************************************************************************/

return mImageView;
}

/**
* 显示当前屏幕的图片，先会去查找LruCache，LruCache没有就去sd卡或者手机目录查找，在没有就开启线程去下载
* @param firstVisibleItem
* @param visibleItemCount
*/
private void showImage(int firstVisibleItem, int visibleItemCount){
Bitmap bitmap = null;
for(int i=firstVisibleItem; i<firstVisibleItem + visibleItemCount; i++){
String mImageUrl = imageThumbUrls[i];
final ImageView mImageView = (ImageView) mGridView.findViewWithTag(mImageUrl);
bitmap = mImageDownLoader.downloadImage(mImageUrl, new onImageLoaderListener() {

@Override
public void onImageLoader(Bitmap bitmap, String url) {
if(mImageView != null && bitmap != null){
mImageView.setImageBitmap(bitmap);
}

}
});

//if(bitmap != null){
//	mImageView.setImageBitmap(bitmap);
//}else{
//	mImageView.setImageDrawable(context.getResources().getDrawable(R.drawable.ic_empty));
//}
}
}

/**
* 取消下载任务
*/
public void cancelTask(){
mImageDownLoader.cancelTask();
}

}


MainActivity  里面一个GridView，然后提供一个系统菜单来删除手机上的缓存图片，直接上代码，比较简单所以里面也没有注释

[java]
view plaincopyprint?





package com.example.asyncimageloader; 

 
import android.app.Activity; 

import android.os.Bundle; 
import android.view.Menu; 

import android.view.MenuItem; 

import android.widget.GridView; 

import android.widget.Toast; 

 
public class MainActivity
extends Activity { 
    private GridView mGridView; 

    private String [] imageThumbUrls = Images.imageThumbUrls;  

    private ImageAdapter mImageAdapter; 

    private FileUtils fileUtils; 

 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 

        super.onCreate(savedInstanceState); 

        setContentView(R.layout.activity_main); 
        fileUtils = new FileUtils(this); 

        mGridView = (GridView) findViewById(R.id.gridView); 

        mImageAdapter = new ImageAdapter(this, mGridView, imageThumbUrls); 

        mGridView.setAdapter(mImageAdapter); 
    } 
 
    @Override 
    protected void onDestroy() { 

        mImageAdapter.cancelTask(); 
        super.onDestroy(); 

    } 
 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 

        super.onCreateOptionsMenu(menu); 

        menu.add("删除手机中图片缓存"); 

        return super.onCreateOptionsMenu(menu); 

    } 
 
    @Override 

    public boolean onOptionsItemSelected(MenuItem item) { 

        switch (item.getItemId()) { 

        case 0: 

            fileUtils.deleteFile(); 
            Toast.makeText(getApplication(), "清空缓存成功", Toast.LENGTH_SHORT).show(); 

            break; 

        } 
        return super.onOptionsItemSelected(item); 

    } 
 
}<span style="font-family: Times New Roman; font-size: 14px;"> 

</span> 

package com.example.asyncimageloader;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.GridView;
import android.widget.Toast;

public class MainActivity extends Activity {
private GridView mGridView;
private String [] imageThumbUrls = Images.imageThumbUrls;
private ImageAdapter mImageAdapter;
private FileUtils fileUtils;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fileUtils = new FileUtils(this);
mGridView = (GridView) findViewById(R.id.gridView);
mImageAdapter = new ImageAdapter(this, mGridView, imageThumbUrls);
mGridView.setAdapter(mImageAdapter);
}

@Override
protected void onDestroy() {
mImageAdapter.cancelTask();
super.onDestroy();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
menu.add("删除手机中图片缓存");
return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case 0:
fileUtils.deleteFile();
Toast.makeText(getApplication(), "清空缓存成功", Toast.LENGTH_SHORT).show();
break;
}
return super.onOptionsItemSelected(item);
}

}<span style="font-family:Times New Roman;font-size:14px;">
</span>

MainActivity的布局文件

[html]
view plaincopyprint?





<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android" 

    xmlns:tools="http://schemas.android.com/tools" 

    android:layout_width="match_parent" 

    android:layout_height="match_parent" 

    tools:context=".MainActivity"
> 
 
    <GridView 

        android:id="@+id/gridView" 

        android:layout_width="match_parent" 

        android:layout_height="match_parent" 

        android:stretchMode="columnWidth"  

        android:columnWidth="90dip"  

        android:verticalSpacing="10dip" 

        android:horizontalSpacing="10dip" 

        android:cacheColorHint="@android:color/transparent" 

        android:numColumns="auto_fit"
> 
    </GridView> 

 
</RelativeLayout> 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<GridView
android:id="@+id/gridView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:stretchMode="columnWidth"
android:columnWidth="90dip"
android:verticalSpacing="10dip"
android:horizontalSpacing="10dip"
android:cacheColorHint="@android:color/transparent"
android:numColumns="auto_fit" >
</GridView>

</RelativeLayout>


因为有网络操作和对sd卡的操作，所以我们必须加上相对应的权限

[html]
view plaincopyprint?





<uses-permission
android:name="android.permission.INTERNET"
/>  
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE"
/>  

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

好了，代码就全部介绍完了，我们运行下程序看看效果，这里的效果是用一个线程下载图片的效果，可能有一些不完整，想看看效果自己动手试试，郁闷，家里的网络卡，gif的图片出不来效果，只能明天上传图片啦,公司也上传不了动画效果，我去，那我就贴一张普通图片，哈哈



好了，今天的讲解到此结束，有疑问的朋友请在下面留言,源码里面GridView的布局文件 columnWedth设置了120dip,有点丑，大家可以改成90dip

源码下载，点击这里 
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